Polyether Polyols Technologies for Rigid Foam Fabrication

2 Polyether Polyol Technologies for Rigid Foam Fabrication 

Polyether polyols for rigid PU foams are obtained in the same type of polymerisation reactors as those used for high molecular weight polyether polyols, i.e., in stainless steel loop reactors, with an external heat exchanger, preferably with the possibility of generating a large surface of the liquid reaction mass, by a spray technique or by an ejector technique 

Reactors used for the synthesis of rigid polyether polyols need an internal stirrer, because frequently high melting point polyols (such as pentaerythritol or sucrose) are used as starters and the initial reaction mass is a suspension of solid polyols in liquid. 

Generally, the polymerisation conditions for polyfunctional polyol alkoxylation, with KOH as catalyst, to rigid polyether polyols are  

For alkoxylation in the presence of tertiary amines, lower alkoxylation temperatures of around 80-95 °C are recommended, because tertiary amines are more active at lower 

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